Transforming UV vertices using numeric values in Blender 2.7
if you hit N, you open a panel which has a field by which you can move vertices precisely.  Blender also allows you to perform mathematical equations in these fields.

As for rotating and scaling, there is no field to type into, but you are able to do it in another way.  After hitting &quot;r&quot; to rotate, you can simply type in the number of degrees to rotate it by.  This also works for scaling, and this can even be applied in the 3D view.
Also, if you open the tool panel (t), you will find two buttons for quickly rotating in 90 degrees, shown by arrows on the picture below.  You can also use the snapping tool, which is circled below.  You can turn it on and off by clicking the magnet button which I circled, or by holding down ctrl.  This will rotate it by 5 degree increments, or scale it by increments.  Blender even shows by how much you are moving/scaling/rotating in numbers where I have drawn the square below.  It only shows it while you are performing the action, however.

Hope this helps you.  Good luck!